Cooling device configured to cool an electronic module

Abstract

The invention relates to a cooling device (3) configured to cool an electronic module (2) comprising in particular an electronic board (4) on which a plurality of electronic components (5) are mounted, the cooling device including: - an enclosure (10) configured to receive the electronic module (2); and - an immersion fluid (100) in which the electronic module (2) is at least partially immersed, the immersion fluid containing a dielectric fluid and at least one material forming an electromagnetic barrier mixed with the dielectric fluid.

Description

DESCRIPTION Title: Cooling device configured to cool an electronic module [1] The present invention relates in particular to a cooling device configured to cool an electronic module. [2] It is known, in the context of cooling a power electronic card, such as that used in a DCDC converter (this converter being intended to transform a voltage of a direct current from a first voltage value to a second voltage value) or a High Voltage inverter, to use a cooling liquid circulating in a plate which is in contact with the electronic card. Such a system involves a significant fluid flow rate and is energy-intensive. In addition, the architecture of the electronic card can complicate access, in terms of cooling, to the hottest components. [3] The present invention aims in particular to further improve the thermal regulation, in particular the cooling, of an electronic module, while allowing good EMC (electromagnetic compatibility) protection. [4] The invention thus relates to a cooling device configured to cool an electronic module comprising in particular an electronic card on which a plurality of electronic components are mounted, the cooling device comprising: - an enclosure configured to receive the electronic module, an immersion fluid in which the electronic module is at least partially immersed, the immersion fluid containing a dielectric fluid and at least one electromagnetic barrier material mixed with the dielectric fluid. [5] In the invention, the components can be completely immersed. [6] Thanks to the invention, the cooling of electronic components is achieved by direct contact with the immersion fluid. [7] Furthermore, the invention makes it possible to reduce / suppress electromagnetic wave emissions that may undesirably interfere with the operation of electronic components. The invention thus makes it possible to obtain good electromagnetic compatibility or CEM (in English, "electromagnetic compatibility" or EMC) protection around the electronic module, in a relatively simple manner, since this electromagnetic barrier is obtained by the immersion fluid itself and there is no need to provide additional CEM barrier components. [8] According to one aspect of the invention, the material forming the electromagnetic barrier is chosen to absorb / attenuate electromagnetic radiations in a predetermined absorption spectral band. [9] According to one aspect of the invention, the predetermined absorption spectrum band contains at least the radio wave spectrum.

[0010] According to one aspect of the invention, the predetermined absorption spectral band contains, in addition to the radio wave spectrum, at least a part of the microwave spectrum and / or at least a part of the long wave spectrum.

[0011] According to one aspect of the invention, the predetermined absorption spectral band covers wavelengths from 10 -2 at 10 8 m.

[0012] By absorbing / attenuating wavelengths in this predetermined spectrum band, the immersion fluid provides good EMC protection.

[0013] According to one aspect of the invention, the dielectric fluid comprises oil.

[0014] According to one aspect of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains molecules having a sufficiently high molar absorption coefficient in the predetermined spectral band, to absorb / attenuate electromagnetic radiation in this predetermined absorption spectral band.

[0015] According to one aspect of the invention, the molecules for absorbing / attenuating electromagnetic radiation are chosen from molecules with rotational transition for absorbing / attenuating electromagnetic radiation, in particular in the microwave spectrum.

[0016] According to one aspect of the invention, the molecules for absorbing / attenuating electromagnetic radiation are chosen from: - anthracene which is a chemical compound with the formula C14H10; water (H2O); nitrogen dioxide (N2O).

[0017] These three examples of molecules allow the absorption / attenuation of electromagnetic radiation in the microwave spectrum.

[0018] According to one aspect of the invention, the immersion fluid contains a single type of molecule for absorbing / attenuating electromagnetic radiation.

[0019] Alternatively, the immersion fluid contains multiple types of molecules to absorb / attenuate electromagnetic radiation. For example, multiple types of molecules are chosen to absorb / attenuate electromagnetic radiation in spectra that are different (e.g., may overlap but remain different).

[0020] According to one aspect of the invention, the molecules are chosen so as to avoid the appearance of electric arcs when the immersion fluid is traversed by an electric current.

[0021] According to another aspect of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains atoms with nuclear spin chosen so that, when subjected to electromagnetic radiation for example in the radio wave spectrum, the atomic nuclei of these atoms absorb the energy of the radiation.

[0022] According to one aspect of the invention, the atoms with nuclear spin are chosen from the following elements: 1 H, 13 C, 17 0, 19 F, 31 P, 129 10th.

[0023] According to one aspect of the invention, the cooling device comprises a device for generating a magnetic field to act on the nuclear spin of the atoms so that they absorb the energy of the radiation.

[0024] According to one aspect of the invention, the device for generating a magnetic field is a self-inductance, in particular belonging to the module to be cooled.

[0025] Alternatively, the device for generating a magnetic field is a self-inductance belonging to a separate component of the module to be cooled.

[0026] According to yet another aspect of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains particles, in particular ferromagnetic particles, in particular of nanometric size.

[0027] According to one aspect of the invention, the particles are dispersed in the dielectric fluid, in particular with the presence of dispersing agents such as charged molecules, surfactants or polymers.

[0028] According to one aspect of the invention, the particles are of metallic type, in particular of ferrite type with iron oxide.

[0029] According to one aspect of the invention, the particles are dispersed in a ferrofluid.

[0030] Ferrofluids are colloidal suspensions of ferromagnetic or ferrimagnetic nanoparticles of about 10 nanometers in size in a solvent. These liquids become magnetic when an external magnetic field is applied while maintaining their colloidal stability.

[0031] Ferrofluids also improve heat transfer within the cooling system. When particles (in the ferrofluid) are heated beyond the Curie temperature, they lose their magnetization and their temperature drops. This creates the equivalent of a heat pump.

[0032] According to one aspect of the invention, the enclosure is formed on a plastic housing or, alternatively, a metal housing, in particular aluminum.

[0033] The invention relates to a system comprising an electronic module and a cooling device as mentioned above, configured to cool the electronic module placed in the enclosure.

[0034] Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and several examples of embodiment given for informational and non-limiting purposes with reference to the appended schematic drawing on the other hand, in which:

[0035] [Fig 1] Figure 1 is a schematic representation, in section, of a system according to an exemplary embodiment of the invention, with an electronic module in an enclosure of a cooling device.

[0036] The features, variants and different embodiments of the invention may be combined with each other in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0037] Figure 1 shows a system 1 comprising an electronic module 2 and a cooling device 3 according to an exemplary embodiment of the invention, configured to cool the electronic module 2.

[0038] Electronic module 2 is part of a DCDC converter, or a high voltage inverter, particularly for motor vehicles.

[0039] The electronic module 2 comprises, for example, an electronic card on which a plurality of electronic components are mounted, including MOSFET type transistors and / or inductors, these examples not being exhaustive.

[0040] The cooling device 3 comprises an enclosure 10 configured to receive the electronic module 2, and to be filled with an immersion fluid 100.

[0041] This immersion fluid is used to cool the components of the electronic module 2 by contact of the immersion fluid 100 with these components.

[0042] The enclosure 10 is formed by a housing 12 made of plastic material.

[0043] The cooling device 3 further comprises a cover 11, also made of plastic, configured to close the enclosure 10 in a sealed manner.

[0044] The enclosure 10 is supplied with immersion fluid via a fluid inlet 14 and this fluid is discharged via the fluid outlet 15 after having circulated in the enclosure 10. The fluid leaves the enclosure 10 hotter than at the fluid inlet 14.

[0045] The fluid inlets 14 and fluid outlet 15 are, for example, part of a fluid circuit equipped with a compressor for the forced movement of the fluid.

[0046] The electronic module 2 is placed for example on pads 17 so that immersion fluid 100 can flow under the electronic module 2.

[0047] The immersion fluid 100 in which the electronic module 2 is immersed contains a dielectric fluid such as a dielectric oil, and an electromagnetic barrier material mixed with the dielectric fluid.

[0048] The electromagnetic barrier material is selected to absorb / attenuate electromagnetic radiation in a predetermined absorption spectral band, which contains the radio wave spectrum and at least a portion of the microwave spectrum and at least a portion of the long wave spectrum.

[0049] The predetermined absorption spectral band covers wavelengths from 10 -2 at 10 8 m.

[0050] By absorbing / attenuating wavelengths in this predetermined spectrum band, the immersion fluid provides good EMC protection.

[0051] In a first example of implementation of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains molecules having a sufficiently high molar absorption coefficient in the predetermined spectral band, to absorb / attenuate electromagnetic radiation in this predetermined spectral absorption band.

[0052] Molecules for absorbing / attenuating electromagnetic radiation are chosen from molecules with rotational transition to absorb / attenuate electromagnetic radiation, particularly in the microwave spectrum.

[0053] Molecules for absorbing / attenuating electromagnetic radiation are chosen from: - anthracene which is a chemical compound with the formula C14H10; water (H2O); nitrogen dioxide (N2O).

[0054] These three examples of molecules allow the absorption / attenuation of electromagnetic radiation in the microwave spectrum.

[0055] The immersion fluid 100 contains a single type of molecule for absorbing / attenuating electromagnetic radiation, multiple types of molecules for absorbing / attenuating electromagnetic radiation. For example, multiple types of molecules are chosen to absorb / attenuate electromagnetic radiation in spectra that are different (e.g., that may overlap but remain different).

[0056] The molecules are chosen so as to avoid the appearance of electric arcs when the immersion fluid 100 is crossed by an electric current.

[0057] In another exemplary embodiment of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains atoms with nuclear spin chosen such that, when subjected to electromagnetic radiation, for example in the scepter of radio waves, the atomic nuclei of these atoms absorb the energy of the radiation.

[0058] Nuclear spin atoms are chosen from the following: 1 H, 13 C, 17 O, 1 9 F, 31 P, 129 10th.

[0059] The cooling device 3 comprises a device for generating a magnetic field to act on the nuclear spin of the atoms so that they absorb the energy of the radiation.

[0060] The device for generating a magnetic field is a self-inductance (or "self-inductance" in English), in particular belonging to the module to be cooled, or is a specific inductance belonging to a component separate from the module to be cooled.

[0061] In yet another example of implementation of the invention, the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains particles, in particular ferromagnetic particles, in particular of nanometric sizes.

[0062] The particles are dispersed in the dielectric fluid, particularly with the presence of dispersing agents such as charged molecules, surfactants or polymers.

[0063] The particles are of metallic type, notably of ferrite type with iron oxide.

[0064] In an exemplary embodiment of the invention, the particles are dispersed in a ferrofluid. Ferrofluids are in particular colloidal suspensions of ferromagnetic or ferrimagnetic nanoparticles of a size of the order of 10 nanometers in a solvent. These liquids become magnetic when an external magnetic field is applied while retaining their colloidal stability. Ferrofluids also make it possible to improve heat transfer within the cooling device. Indeed, the particles (in the ferrofluid) heated beyond the Curie temperature lose their magnetization and drop in temperature. This is how the equivalent of a heat pump is obtained.

Claims

CLAIMS

1. Cooling device (3) configured to cool an electronic module (2) comprising in particular an electronic card (4) on which a plurality of electronic components (5) are mounted, the cooling device comprising: - an enclosure (10) configured to receive the electronic module (2), an immersion fluid (100) in which the electronic module (2) is at least partially immersed, the immersion fluid containing a dielectric fluid and at least one material forming an electromagnetic barrier mixed with the dielectric fluid.

2. Cooling device (3) according to the preceding claim, in which the electromagnetic barrier material is chosen to absorb / attenuate electromagnetic radiation in a predetermined absorption spectral band, the predetermined absorption spectral band containing in particular at least the spectrum of radio waves.

3. Cooling device (3) according to the preceding claim, wherein the predetermined absorption spectral band contains, in addition to the radio wave spectrum, at least a part of the microwave spectrum and / or at least a part of the long wave spectrum.

4. Cooling device (3) according to one of the preceding claims, wherein the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains molecules having a sufficiently high molar absorption coefficient in the predetermined spectral band, to absorb / attenuate electromagnetic radiation in this predetermined spectral absorption band.

5. Cooling device (3) according to the preceding claim, in which the molecules for absorbing / attenuating electromagnetic radiation are chosen from molecules with rotational transition for absorbing / attenuating electromagnetic radiation, in particular in the microwave spectrum.

6. Cooling device (3) according to the preceding claim, wherein the molecules for absorbing / attenuating electromagnetic radiation are chosen from: anthracene which is a chemical compound of formula CuH; water (H2O); nitrogen dioxide (N2O).

7. A cooling device (3) according to claim 5 or 6, wherein the immersion fluid contains a single type of molecule for absorbing / attenuating electromagnetic radiation, or several types of molecule for absorbing / attenuating electromagnetic radiation. For example, several types of molecules are chosen to absorb / attenuate electromagnetic radiation in spectra that are different (e.g., that may overlap but remain different).

8. Cooling device (3) according to one of the preceding claims, wherein the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains atoms with nuclear spin chosen so that, when subjected to electromagnetic radiation for example in the scepter of radio waves, the atomic nuclei of these atoms absorb the energy of the radiation.

9. Cooling device (3) according to the preceding claim, in which the atoms with nuclear spin are chosen from the following elements: 1 H, 13 C, 17 0, 19 F, 31 P, 129 10th.

10. Cooling device (3) according to one of the preceding claims, in which the electromagnetic barrier material capable of absorbing / attenuating predetermined electromagnetic radiation contains particles, in particular ferromagnetic, in particular of nanometric size, the particles being in particular of metallic type, in particular of ferrite type with iron oxide.

11. Cooling device (3) according to the preceding claim, wherein the particles are dispersed in a ferrofluid.

12. Cooling device (3) according to one of the preceding claims, in which the enclosure (10) is formed on a housing (12) made of plastic or, alternatively, of metal, in particular aluminum.

13. System (1) comprising an electronic module (2) and a cooling device (3) according to one of the preceding claims, configured to cool the electronic module placed in the enclosure (10).

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